Mysterious Coolant Leak...

[NOS2006]

About every 4 months or so (this has happened twice), my car's (1998 3.8 A4 Camaro) temperature gauge goes crazy, up and down like it's overheating. I check the coolant, which gets very low, fill it up, and it's fine for another 4 months. Well, week ago this happened for the second time and I decided to bring it to a shop for checks because my SES light is on now too. It's throwing two codes, both for P0147 (HO2S Heater Circuit Bank 1 Sensor 3 - Post Converter). Well we figured it might be a head gasket, so after getting it tested with a pretty insufficient test, they said yes.

Well I brought it somewhere else and after over 4 hours of testing, they cannot find any leaks anywhere... not the radiator, gaskets... anywhere. Now I'm ****ting bricks because I don't know what's going on. You guys have any suggestions?

[grh_1993_V6]

... I have had my 3.4 for about 8 months now with the same problem.. it gradually got worse (filling water once a week) then finnaly today i found a large crack in the radiator.... dealer even pressure tested system and found nothing in december and again in march... now I need a radiator and the closet one is in Los Angeles...any one have one for sale? that could ship it quick possibly.

[black98V6]

I'd put money it's the waterpump man. They aren't too expensive and are easy to change.

[StudlyCamaro]

sounds like the thermostat is just sticking 8$ fix

the coolant isnt leaking really, its boiling off thru the raidiator cap

[Heartbeat_of_94]

that happened to me when my waterpump and my thermo was a screwed up. got those two things fixed and no problems since.

[camaronat]

Also, you may have a front cover leak. (covers timing chain, behind the waterpump). Mine would only leak when the engine was warm, so it never left any puddles.